export type EntryHandler = (entry: IntersectionObserverEntry) => void;
export type Unobserve = () => void;
export type Observe = (element: HTMLElement, entryHandler: EntryHandler) => Unobserve;
export declare class ViewportTracker {
    /**
     * @private
     */
    private elementHandlerMap;
    /**
     * @private
     */
    private observer;
    /**
     * @private
     */
    private queueSet;
    /**
     * Method to set scrollable viewport as root for the IntersectionObserver, returns
     * cleanup function to be invoked upon disposing of the DOM element to prevent memory leaks
     *
     * @param viewportElement
     * @param options
     * @returns Unobserve
     */
    setViewport: (viewportElement: HTMLElement, options?: Pick<IntersectionObserverInit, "threshold" | "rootMargin">) => () => void;
    /**
     * Method to set element to observe and handler to be triggered whenever IntersectionObserver
     * detects a possible change in element's visibility within specified viewport, returns
     * cleanup function to be invoked upon disposing of the DOM element to prevent memory leaks
     *
     * @param element
     * @param handler
     * @returns Unobserve
     */
    observe: Observe;
}